hcg diet

I have a cousin who is very obese who wants to do this and I'm trying to convince them NOT to do it cause it isn't a good diet. 500 calories a day and injecting hcg is what it is. they will not listen to me. can you help give me the science why this does not work so i can show that to them...

So should I do the HCG diet? Do I just get HCG from a doctor? Or is it something I can order online? I would do injections. From what I have read, thats the only way. Everything else is BS. I have Phentermine now to help with hunger. So thought together might be the end of the beer belly.

Whats the best workout for overweight people?